Process for extraction



PROCESS FOR EXTRACTION Filed June 7, 1937 000 5 sw m/qr 3 F. D M WM .5 M 5 amp V i WW7 5 5W 0 WW H N n w 9 7 M U M w r M w m W W mm H 0 w D g m Q l C C 6 1v N 7 bx 4 Q =5 Q 2 i 4 5 a M m W M W M ma w Patented July 8, 1941 2,248,619 P OCESS FOR. EXTRACTION Louis Freedman, Mount Vernon, and Harry Ennis Dubin, New Rochelle, N. Y., assignors to U. S. Vitamin Corporation, New York, N. Y., a cor-' poration of Delaware Application June 7, 1937, Serial No. 146,776

7 Claims. (Cl. 167-81) This invention relates to an apparatus and to a process for the extraction of a substance from a liquid medium by a second liquid medium. More particularly, it is concerned with the extraction of a vitamin from an oleaginous material having a vitamin bearing ,diflicultly saponifiable fraction by contacting with an immiscible solvent of a difierent specific gravity, and includes correlated improvements and discoveries whereby the extraction of a substance may be enhanced.

Various methods have in the past been described for the extraction of the non-saponifiable fractions from oils, such as fish liver oils,

by converting the oils into soaps and extracting" the non-saponifiable fraction therefrom by means of various solvents. The methods of extracting the non-saponifiable fraction have been described from the standpoint of the chemistry of the extraction rather than from the mechanics of the extraction.

In these prior processes, the extraction operations on a commercial scale have been beset by various difliculties, chiefly of a mechanical and physical nature. Some of the difficulties from an economical standpoint, are large and costly apparatus, multiplicity of operations requiring excessive labor charges, large volumes of solvents,-

and mechanical difiiculties obvious to those skilled in the art. Physical difficulties involved in the heretofore described processes are absorption or emulsification of the solvent by the soap, resulting in slow or incomplete extraction of the non-saponifiable fraction by the solvent; repeated washings or leachings of the soap with large volumes of solvent resulting in loss of time in the extraction and settling or separation of the soap and solvent layers, and recovery of enormous' volumes of solvent with attendant losses thereof.

In a process of continuous extraction, particularly as in the continuous extraction of vitamins in the non-saponifiable or difiicultly saponifiable matter from soap solutions prepared from fish liver oils, eflicient and economical extraction of the vitamins are difiicult because of improper percolation of the solvent through the soap, particularly if the mixture is not agitated. Agitation increases the percolation effect, but results in troublesome emulsions between the soap and solvent, thereby interfering with the extraction efiectiveness of the solvent.

Direct extraction of vitamins from soap solutions by percolation of the solvent from below, when using a solvent of lower specific gravity than the soap solution, e. g., ether, or as in the case of a solvent of higher specific gravity than the soap, such as chloroform, ethylene dichloride, and other chlorinated hydrocarbons,

where the solvent enters from above, is time consuming, requires several days to extract one batch of commercial size, and enormous volumes of solvent are used. Further when the solvent containing extracted vitamins is recovered continuously and simultaneously with the extraction medium which is immiscible with and of different specific gravity than the first medium, but which is a solvent for the extractable substance.

A further object of the invention is an improved process for the extraction from oils, fats, waxes, etc., of animal, vegetable or mineral origin of substances dissolved or otherwise held therein by means of an immiscible solvent of different specific gravity than the medium in which the dissolved substances were originally contained.

Another object of the invention is an improved process for the continuous extraction from oils, fats, waxes and tissues of animal or vegetable origin, of the non-saponifiable or difficultly saponifiable matter contained therein.

An additional object of the invention is an improvedprocess for the continuous extraction of vitamins contained in the non-saponifiable fraction of oils and fats of animal or vegetable origin, or any fat containing animal or vegetable tissue.

A still further object of the invention is the provision of an apparatus for the continuous extraction of vitamins contained in oils, fats and tissues of animal or vegetable origin, by extracting from a soap prepared from such materials, the non-saponifiable fractions containing the desired vitamins, by a solvent of different specific gravity and immiscible with said soap.

A more particular object of the invention is an improved and economic process for the continuous extraction of vitamins contained in fish livers and fish liver oils, and an apparatus for carrying out the said process.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to eifect such steps, all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which there is shown the apparatus in which the extraction procem may be eflected.

The apparatm comprises in combination, Fig. 1, an enclosed cylindrical tank I constructed of wood; stoneware, steel. or any other metal or material suitable for the type of extraction involved, and having a height to diameter ratio of approximately 3.4 to 1.; and a removable shaft 2 extending from a drive support 3 to foot bearing 4: and fastened to said shaft by welding or otherwise, a series of novelly constructed bailie blades I spaced apart at specified distances.

The bame blades, illustrated in detail in Fig. 2, are, preferably, in the shape of discs of which one-halfoi' the circumference is circular and the other half elliptical, the shortest radius of the ellipse being upwards to one-half the radius of the circular part of the disc and desirably in the ratio of about 1 to 1.4 to 1.8. The battle blades of semi-circular, semi-elliptical form may, desirably, be placed on the shaft in staggered positions, with the long radius and the short radius in alternation. The longest radius of the baffies is only slightly less than the radius of the extractor tank, and the difference suitably is only the space necessary to allow for clearance between the walls of the tank, and the perimeter of the baiiie. Spacing of the blades on the shaft is, preferably, at a distance approximately equal to the shortest radius of the elliptical part of the blade. Such spacing may, however, be varied up or down, and the number of blades may be varied, depending on the type of extraction to be made and also on the size of the extractor.

As an illustrative embodiment of a manner in which vitamins contained in a non-saponiflable fraction of a water soluble soap solution prepared from cod liver oil may be extracted, the following description is presented.

A soap solution may be prepared by treating an oil or oil bearing material with a caustic alkali. A potassium or sodium soap is preferred due to easier solubility in water, and in wateralcohol mixtures. The soap solution may be an all aqueous solution, or it may be a mixture of water and ethyl alcohol, or other alcohol readily miscible with water. Other substances or solvents may be added to the soap prior to extraction, either to reduce the emulsifying effect of the soap, or to increase the extraction effect of the solvent on the unsaponiflable matter. In general, the soap solution contains a sufllciently high percentage of water so as to be substantially immiscible with the solvent to be used for extraction.

The solvent used may be ethylene dichloride, which has a specific gravity of approximately 1.255, chloroform, carbon tetrachloride, or other chlorinated hydrocarbon which is a good lipoid solvent. Other solvents that may be utilized are ethers, as ethyl ether, ligroin and other petroleum ethers.

2500 parts of cod liver oil are mixed in a suitable vessel with 2000 parts ethyl alcohol. A solution of 675 parts of potassium hydroxide dissolved in 450 parts of water are added carefully with agitation. The mixture is heated at reflux temperature for 1 to 1% hours, or until saponiflcation is completed. Displacement of the air in the saponification vessel by nitrogen or other inert non-oxidizing gas helps to protect the vitamins from oxidation. The saponiilcation mixture is cooled and a mixture of 7500 parts water and 1750 parts of 95% ethyl alcohol added. The resulting soap solution contains approximately 25% alcohol by volume.

During the extraction, using as solvent ethylene dichloride for example, a certain amount of the ethylene dichloride will be absorbed by the soap solution and a certain amount of the alcohol present in the soap will go into the solvent, so that at the end of the extraction. as we have found by analysis, the soap solution will contain approximately 18% by volume of ethylene dichloride and the ethylene dichloride will contain approximately 3% by volume of ethyl alcohol. Consequently, by virtue of the mutual solubilities of ethyl alcohol and ethylene dichloride, an equilibrium is reached, and this equilibrium is maintained throughout the extraction. It is apparent, therefore, that under the conditions of this equilibrium, the most advantageous conditions for extraction are maintained. Therefore, if the solvent and soap solutions are adjusted to this equilibrium before the start of the extraction, optimum conditions for extraction will prevail from the start.

To the soap solution are now added 3250'parts of ethylene dichloride to give a mixture containing approximately 18% ethylene dichloride (by volume).

The extractor, shown in Fig. l, is charged through nozzle 1 with ethylene dichloride to which has been added 95% ethyl alcohol to give a mixture containing approximately 3% alcohol by volume.

The amount of solvent may be varied depending on the quantity of soap, but in general, if the extractor is used to capacity, the height of the solvent in the extractor should be up to nozzle ill, or a distance below the overflow nozzle 8 sufiicient to allow a head of soap to accumulate before overflowing.

The soap solution contained in a soap reservoir (not shown) flows by gravity by means of a conduit through nozzle 9, situated on the side near the bottom, into the extractor. Rate of flow of the soap, regulated by a valve, is such that the soap being lighter than the solvent, rises at a definite and predetermined rate through the solvent in the general direction indicated by the arrows i. e., through a determinate screw threadlike path until it overflows through nozzle 8, and runs by way of a conduit into ,a spent soap receiver. 7

The stream of soap solution enters the tank via nozzle 0 strikes the non-miscible solvent, and as it rises through the heavier solvent, is broken up into globules or bubbles by the revolving blades or discs. The passage of the soap globules through the solvent is so delayed by the baffling effect of the staggered revolving discs, that they contact a large surface of the solvent giving up to the solvent the non-saponifiable fraction which contains the desired vitamins, and was dispersed in or held by the soap solution. As the globules of soap continue to rise, they successively strike the revolving ballling discs, are retarded in their rate of rising and broken up into smaller globules, so that the globules of soap near the top of the extractor are only a fraction of the size of the globules of soap at the bottom of the extractor. The shaft to which the discs are fastened is connected to a variable speed drive by means of a coupling arrangement, and is revolved at a moderate speed sufiicient to act as moving baflles but still not fast enough to cause emulsification of the soap with the solvent.

In this process, only one liquid, i. e., the soap solution, is actually flowing in a vertical direction whereas the solvent is from the standpoint of a vertical flow, practically stationary, although there is by virtue of the stirring effect of the baffling discs, a fiow of the solvent in a circular motion. The baflling and retarding action on the soap globules has an effect which is that of a column many times its height.

Observation glasses I I are located in both sides of the extractor diametrically opposite to each other, and provide for visual observation of the extraction process.

Extraction of vitamins can be accomplished in from three to six hours depending on the size of'the batch, and from 90 to 95% of the vitamins present in the original material can be removed in one extraction. If desired, a second extraction of the soap can be made by simply running the soap again through the same or a fresh lot of solvent. Thus, two extractions of each lot of soap may be made with one lot of solvent yielding from 95 to 100% of the original vitamin content.

The foregoing procedure provides a process for the continuous extraction of vitamins from fish livers, fish liver oils and other animal or vegetable material, which materially avoids many of the difiiculties previously encountered; which is economical to operate commercially from the standpoint of mechanical equipment, cost of labor, and utilization of time; and, which results in the recovery of high yields of a vitamin-containing fraction without material loss of potency.

The process accordingly efiects an extraction by a combination of procedural steps, which comprises contacting a liquid medium containing a substance to be extracted, especially a vitamin from a soap solution, with a second liquid medium which is substantially immiscible with and of difierent specific gravity than the first medium, but which is a solvent for said substance,

by passing one of these mediums unidirectionally through the other in a retarded, preferably continuous, flow, along predetermined or determinate screw thread-like paths or channels and with continuously increasing subdivision of the fiowing medium thereby affording increased surface contact. It is advantageous in order to insure a high yield and under certain conditions it will be preferable, that the extraction be carried out in an inert atmosphere such as nitrogen or other non-oxidizing gas.

In the above description the soap solution enters at the bottom and rises to the top through the solvent of higher specific gravity. This procedure may be reversed. Thus, the soap solution may be charged into the extractor and the structed with a fan-shaped twist and revolved so as to give an additional upward retarding force to overcome the increased downward flow of the solvent due to force of gravity.

If a solvent of lower specific gravity than the soap, as for example, ethyl ether, ligroin, or other petroleum .ether, is used, then it is advantageous to charge the soap into the extractor and percolate the solvent through the soap solution from the 'bottomto the top, thus allowing the force of gravity to assist in the retarding and baffling enect. The operation is carried out as hereinbefore described, with the exception that the procedure of adding soap and solvent are reversed.

While we have above described the construction of the apparatus according to shape, size and dimensions, particularly the revolving baffling discs, it will be understood that we do not 'height to diameter of the extractor may vary from the given ratio of 3.4 to 1 It may be 2.0 to 1; or 4 or 5 to 1, respectively. In general, the

- higher the ratio, the more efficient the extraction,

and for commercial purposes, the diameter should be large enough to give desired volume without departing too much from convenience of height.

The process utilizes the baflling and retarding effect of the revolving discs on the passage of the soap solution through the solvent in such a manner as to cause the breaking up of the soap into small globules which results in maximum extraction in a short time without causing emulsification of the soap solution and solvent.

Moreover, the method is not limited to the extraction of vitamins from soap solutions prepared from the original oils containing the vitamins, nor to the extraction from soap solution of the non-saponifiable matter originally contained in fish livers, fish liver oils, or other animal or vegetable material. It may be, used for the extraction of substances dissolved or otherwise held in one medium by a second medium of different specific gravity and immiscible with the first medium.

Thus, it may be used for direct extraction from fish oils, fish liver oils, and the like, without saponification of the oils, of vitamins contained therein, by means of a solvent of appreciably different specific gravity and immiscible with the oil, as for instance, methyl, ethyl, propyl and isopropyl alcohols. In general, the aliphatic alcohols of lower molecular weight, and which are miscible with water, are well adapted for this purpose.

Furthermore, other oils, such as lubricating oils, mineral oils, and the like, may have im-' purities, contained therein naturally or added for purposes of refining, extracted by means of an immiscible solvent having different specific gravity.

Since certain changes in carrying out the above process and in the constructions set forth, which embody the invention may be made without departing from its scope, it is intended that all mat-, ter contained in the above description, or shown in the accompanying drawing, shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween,

contactin a liquid medium containing a substance to be extracted with a second liquid medium which is substantially immiscible with and of diilerent specific gravity than the first medium but which is a solvent for said substance, by passing one of said mediums unidirectionally through the other, which remains substantially stationary, in a retarded fiow, through a determinate screw thread-like path, and with continuously increasing subdivision of the flowing medium thereby affording increased surface contact.

2. A process for extraction, which comprises contacting a liquid medium containing a vitamin with a second liquid medium which is substantially immiscible with and of dififerent specific gravity than the first medium but-which is a solvent for said vitamin, by passing one of said mediums unidirectionally through the other, which remains substantially stationary, in a retarded flow attended by repeated contacts between the liquid media, through a determinate screw thread-like path, and with continuously increasing subdivision of the flowing medium thereby affording increased surface contact.

3. A process for extraction, which comprises contacting a soap solution containing a vitamin with a liquid medium which is substantially immiscible with and of different specific gravity than said soap solution but which is a solvent for said vitamin, by passing said soap solution unidirectionally through said liquid medium, which remains substantially stationary, in a retarded flow, through a determinate screw threadlike path, and with continuously increasing subdivision of the soap solution thereby affording tainingmaterial, by passing said soap unidirectionally through the liquid medium, which remains substantially stationary, in a retarded fiow, through a determinate screw thread-like path, and with continuously increasing subdivision of said soap thereby affording increased surface contact.

5. A process for extraction, as defined in claim 4, in which the non-saponifiable and difllcultly saponifiable material containing a vitamin belongs to the group consisting of fish livers and fish liver oils.

6. A process for extraction, which comprises converting an oleaginous material containing a vitamin into a water soluble soap solution by saponification thereof with an aqueous alcoholic solution of a caustic alkali whereby a soap containing vitamins is obtained, mixing the resulting soap solution with a water-miscible alcohol, and contacting the water-alcohol-soap solution so obtained with ethylene dichloride by passing the said solution unidirectionally through the ethylene dichloride which remains substantially stationary, in a retarded flow, through a determinate screw thread-like path, and with continuously increasing subdivision of the soap thereby affording increased surface contact.

'7. A process for extraction, which comprises converting an oil containing a vitamin into a water soluble soap solution by saponification of said oil with an aqueous alcoholic solution of a caustic alkali whereby a soap containing vitamins is obained, admixing the resulting soap solution with a water-miscible alcohol, adding to the water-alcohol-soap solution thus obtained an amount of ethylene dichloride which is sufilcient substantially to saturate such solution, adding to a quantity of ethylene dichloride an amountof 

